Disclosed is a method for producing nanoparticles wherein atoms or molecules constituting a nanoparticle precursor are adhered to an ionic liquid. This method enables to produce nanoparticles which hardly agglomerate in a liquid without chemically modifying the surfaces of the nanoparticles. In addition, since nanoparticles are directly produced from a nanoparticle precursor in this method, the nanoparticles can be produced without requiring complicated operations and without producing by-products.